He grew up hating humanity, but befriended fellow mutant Charles Xavier. However, their ideological differences separated them. While Xavier went and formed his X-Men Erik, now Magneto, formed the Brotherhood of Mutants.

At some point he had two children, Quicksilver and Scarlet Witch. However, Scarlet Witch was too powerful to control her own powers so he sent her to an asylum where she could seek help.

While the Brotherhood fought the X-Men, Magneto built Asteroid M as a haven for mutants. He located the Crimson Gem of Cyttorak and used it to greatly enhance a mutant's abilities. He then pitted the Brotherhood against the X-Men to see who was stronger, then captured the winner. However, Mystique, who had lost, was resentful and betrayed him. The "losers" found Asteroid M and destroyed it.

He used the Project: Rebirth technology, used to make Captain America, to de-age himself healing many of his health problems.

He arranged so that the existence of mutants would be made public in a large fight against a large Sentinel robot. However, Mystique released his daughter who nearly killed him by stopping his powers. Luckily, Quicksilver saved him at the last second making it appear as though he had died.

Scarlet Witch then went around hunting her father, and using Quicksilver as bait. Eventually he used Mastermind to change her memories to make her think he was a good father, and she willingly joined his cause.

When he found out about Mesmero's plan to release the ancient mutant Apocalypse, Magneto made stopping them his new mission. However, he was apparently killed then turned into a Horseman of Apocalypse along with Xavier, Mystique, and Storm. He was eventually saved by the Brotherhood, Acolytes, and X-Men then helped by his two children. When Xavier read Apocalypse's mind, he saw that Magneto was an ally of the X-Men.

Magneto also cares for his daughter. However, years of separation made her detest him. He only wanted the best help for her, but she just saw abandonment. Once she escaped, she went on a rampage to find him. He eventually had Mastermind change her memories so they could get along and have a peaceful family.